A Technique for Evaluating Floatability of Coal Fines, Using Methanol Solutions

Abstract

Small scale “frothless” flotation tests were carried out on narrow size fractions of several coal samples, in a series of aqueous methanol solutions of decreasing surface tension. The results presented as variation of cumulative yield versus cumulative ash content constitute optimum flotation response curves analogous to washability curves in sink-float tests. Flotation behaviour of different coals from the East Kootenay coalfield, British Columbia, was assessed relative to petrographic composition, rank, extent of weathering and inherent ash content. Differences in coal floatability caused by small degrees of weathering could be detected despite lack of differentiation by conventional tests on bulk coal properties.